[R] Replace missing values in lapply

[Dimitris Rizopoulos]

you need to return x in the function within lapply(), e.g., something 
like

lapply(TP, function(x) { x[is.na(x)] <- 0; x })


I hope it works.

Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/(0)16/336899
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Web: http://med.kuleuven.be/biostat/
     http://www.student.kuleuven.be/~m0390867/dimitris.htm



----- Original Message ----- 
From: "Doran, Harold" <HDoran at air.org>
To: <r-help at stat.math.ethz.ch>
Sent: Wednesday, January 24, 2007 4:40 PM
Subject: [R] Replace missing values in lapply


>I have some matrices stored as elements in a list that I am working
> with. On example is provided below as TP[[18]]
>
>> TP[[18]]
>      level2
> level1  1  2  3  4
>     1 79  0  0  0
>     2  0  0  0  0
>     3  0  0  0  0
>     4  0  0  0  0
>
> Now, using prop.table on this gives
>
>> prop.table(TP[[18]],1)
>      level2
> level1   1   2   3   4
>     1   1   0   0   0
>     2
>     3
>     4
>
> It is important for the zero's to retain their position as this 
> matrix
> will subsequently be used in some matrix multiplication and hence, 
> must
> be of dimension 4 by 4 so that is it conformable for multiplcation 
> with
> another matrix.
>
> In looking at the structure of the object resulting from prop.table 
> I
> see NaNs, and so I can do this
>
>> rr <- TP[[18]]
>> rr[is.na(rr)] <- 0
>> rr
>      level2
> level1  1  2  3  4
>     1 79  0  0  0
>     2  0  0  0  0
>     3  0  0  0  0
>     4  0  0  0  0
>
> This is exactly what I want for each matrix. But, I have multiple
> matrices stored within the list that need to be changed and so I am
> trying to resolve this via lapply, but something is awry (namely the
> user), but I could use a little help.
>
> I was thinking the following function should work, but it doesn't. 
> It
> reduces each matrix within the list to a 0.
>
> PP <- lapply(TP, function(x) x[is.na(x)] <- 0)
>
> Am I missing something obvious?
>
> Harold
>
>
> [[alternative HTML version deleted]]
>
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